This ACTG study is a phase II multicenter open-label study designed to evaluate 2', 3'dideoxycytidine (ddC) in the treatment of children with symptomatic HIV infection who are either intolerant to AZT or who show signs of disease progression while receiving AZT. The study objective is to evaluate and compare the long-term safety, tolerance and efficacy of two doses of ddC taken orally every 8 hours in children with symptomatic HIV infection who qualify for the study.